Active Matrix Organic Light Emitting Diode (AMOLED) has been widely adopted in various applications. Organic light-emitting diodes (OLED) are often used as the light-emitting pixel units in AMOLED display devices. In an AMOLED display device, driving thin film transistors (TFTs) are often operated in saturation region so that the driving TFTs may generate driving currents. The driving current may power the OLEDs to emit light.
However, driving currents may cause the TFTs and OLEDs to age. Higher driving currents often cause the OLEDs and the TFTs to age faster. When used in display devices, aged TFTs and OLEDs may appear as screen burn-ins. Further, as the display device ages, the screen burn-ins may become more apparent and severe.
Screen burn-ins often occur when a static image is displayed at a high intensity level (i.e., high gray scale) for a long time on a display panel. Dynamic images on the display panel may change contents all the time. The driving current of the TFTs and OLEDs relating to dynamic images may change according to content variations. Therefore, the aging of the TFTs and OLEDs relating to the dynamic image displays may be balanced over time.
However, contents of static images on the display panel usually remain unchanged over a period of time. Further, when a static image has high intensity levels, the driving currents of the TFTs and OLEDs relating to the static image stay at high levels. Therefore, on a display panel, TFTs and OLEDs relating to static images may age faster than TFTs and OLEDs relating to dynamic images.
Existing technologies often change the size of a static image in a very small scale, or move a static image towards various directions of slight distances. Thus, the static image may become a dynamic image to prevent screen burn-ins. However, in practice, to prevent noticeable changes in the display to users, the static image may not be shifted or resized at a significantly. A major portion of the static image may still remain at high intensity levels, thus causing screen burn-ins on the display panel.